Gas detector



Oct. 26, 1937. H. A. DODGE ET AL GAS DETECTOR Filed Aug. 24, 1935 2Sheets-Sheet 1 THEI ORNEY Oct. 26, 1937. H. A. DODGE ET AL GAS DETECTORFiled Aug. 24, 1933 2 Sheets-Sheet 2 H K 5 R Rm T ODE O A5 NYE l L R A HHC Patented Oct. 26, 1937 UNITED STATES 2,097,182 GAS nE'rEc'roa HarryA. Dodge, and Charles]. Dietrich, New

York, N. Y.

Application August 24, 1933, Serial No. 686,594

4 Claims.

invention is not limited to the automatic detection of gases, vapors andthe like of explosive nature, and is useful in detecting gases, vaporsand the like afiecting generally a predetermined atmosphere.

In general our invention comprises a lamp or other source of a flame,with which is combined thermostat means responsive to an elevation ordepression of temperature, whereby to produce a signal'either audible,visual or otherwise perceptible.

In greater particular, as applicable to an electrical type of system,such thermostat or other suitable means responsive to variation oftemperature controls electrically actuated devices, usually including arelay, the arrangement being such that upon variation of electriccurrent arising from variation of temperature the signal is operated.The electrical circuit inclusive of the thermostat means is preferablyof the closed circuit type, to thereby insure continuity of operativecondition with which advantage is coupled the additional safeguard thatupon breaking or other substantial change in the detecting circuit, thesignal is operated.

More preferred forms of our system are of such nature that a pluralityof unit assemblies, each unit including a lamp and thermostatic means,may be connected by common wiring. In the most preferred forms of theinvention, a separate signal or group of signals is arranged for eachassembly unit, whereby the assembly unit affected by the presence ofexplosive or other deleterious gas, vapor or the like is selectivelyindicated.

Most advantageously, the thermostat means comprises a set of thermostatelements individually respectively responsive to increase of temperatureand to decrease of temperature, whereby under the condition of thepresence .of a gas of explosive nature, that is to say, tending to in- 3crease the temperature of the flame, the thermostat element responsiveto increase of temperature efiects the operation of the signal, and,similarly, upon the condition of decrease of temperature of the. flamedue to the presence of noncombustible or less combustible gas, vapor orthe like, the thermostat element responsive to decrease of temperatureeifects the operation of the signal.

Combined with our temperature responsive means, we provide a flameextinguishing means whereby in the circumstance of use in a mine orother locality the presence of an explosive gas, vapor or the likeentails the danger of explosion, or the danger of asphyxiation or otherdanger leading to irreparable or serious results. In systems embodyingour flame extinguishing means, the operation of the same is hadadditively to that of eifecting and localizing the danger of thedeleterious gas. v

Further features and objects of the invention will be more fullyunderstood from the following detail description and the accompanyingdrawings, in which Fig. 1 is a diagrammatic view of an electrical.circuit arrangement, illustrating an embodiment of our invention.

Fig. 2 is a detail diagrammatic view of certain parts at a certainoperated stage.

Fig. 3 is a detail diagrammatic view corresponding to Fig. 2 but showinganother stage of operation.

Fig. 4 is a sectional view of one manner of assembly of a lamp andtemperature variation responsive means; and

Fig. 5 is a plan view on the line 5-5' of Fig. 4.

Referring to the drawings, a typical lamp suitable for the purpose isindicated at III. In the application of the invention to mines and otherlocations subject to the presence of inflammable gases, such lamp I0 isprovided with suitable means for minimizing explosion. A typical form oflamp for mines, pursuant to present practice, comprises a metal gauzeabove and completely surrounding the flame, to retard the passage ofignited gas through the gauze. The particulars of preferred forms of thelamp, per se, are set forth hereinafter.

As is diagrammatically illustrated in Fig. 1, the lamp I 0 is providedwith a flame-extinguishing mechanism I l of suitable arrangement whichis releasable in response to the presence within the region of the flameof gases, either explosive, asphyxiating or otherwise deleterious,affecting the flame either to increase or decrease its temperature.trated in Fig. 1, comprising asnuifer element l2, in the form of a cap,which cap may be of metal. or other material, such as lavaor the like,00- ordinated in an electrical system, in which arrangement the cap I2may be attached to a lever One such suitable arrangement is illus- I3,pivoted at I4 and either of or embodying a suitable section of magneticmaterial, for cooperation with an electromagnet I5 having a ferrous coreI6.

Associated with the flame I0a of the lamp are suitably arrangedthermostatic means responsive to increasing and decreasing temperaturesof the flame. Advantageousl'y, such temperature variation responsivemeans is in the form of a thermostatic element I1 responsive to increaseof the temperature and a thermostatic element I8 responsive to decreaseof temperature.

One form of circuit arrangement of the above stated parts and thedesired signalling devices, as illustrated in Fig. 1, comprises abattery I9, which may be a storage battery, supplied with current by anautomatic charger 20, energized from the Dower lines 2I, 22.

A conductor 23 connects one end of. the battery I9 with a conductor 24leading to the thermostat elements, say, to one terminal I8a of thethermostat element I8, its other terminal I8b being connected by aconductor 25 to one end of the winding I 5, the opposite end of thewinding being connected by a conductor 26 to a conductor 21. Oneterminal I1a of the thermostat element I1 is connected by a lead 28 tothe terminal I 8b of the thermostat element I8; its other terminal I")is connected to a conductor 21.

The conductor 21 leads to the winding 300 of a relay 30, or othersuitable device, for actuating the signal means. In the drawings we haveindicated three forms of signals, to wit, an audible alarm '3I such asan electric hell or equivalent, a

visual alarm such as an electric lamp 32, and semaphore 33 and/orequivalent.

The relay 30 is of the combined pivoted armature and solenoid type,having the pivoted armature 44 provided adjacent its free end with abridging member 63 adapted to engage with the contacts 35 and 36.Attached to the free end of the armature 44 is the semaphore 33 adaptedto serve as a visual signal device. Associated with the armature 44 is acore 30a of magnetic material provided on its end with a piece of brass,copper, or other non-magnetic material 30b and which is interposedbetween the armature 44 and core 30a. Surrounding the core 30a is a coilI30, one end of which is connected to the conductor 21 and the other endto the conductor 32. Normally, current is passing through the coil I30and therefore the armature 44 is attracted to the core 30a and thebridging member 63 is maintained out of engagement with the contacts 35and 36. Gravity is ordinarily sufficient to cause the movement of thebridging member 63 into engagement with the contacts 35 and 36 uponfailure of the circuit through the coil I30 or from any other cause,though a spring 45 or equivalent device may be employed to ensure suchaction. Associated with the armature 44 and coil I30 is the solenoid 30cprovided with a plunger armature 30!. To one end of the plunger armature30f is attached one end of a spring 30g, the other end of this springbeing attached to one end of an 32, and the solenoid 30c and coil I30are arranged in parallel.

Normally the current from the conductor 21 to the conductor 32 flowsthrough the. solenoid 30c and coil I30 alike. The plunger armature 30fof the solenoid 300 is pulled into the solenoid against the spring 30gand toward the armature 44. The core 300. is magnetized and will holdthe armature 44 against the non-magnetic member 30b. The. pressure ofthe plunger armature 30) against the armature 44 is not suflicient,under the assumed conditions, to overcome the holding power of the coilI 30. When, however, the current through the coil I30 and solenoid 300is increased due to a short circuit or due to the operation ofthermostat I1 (which shunts out coil I5 and therefore increases thepotential across the coil I30 and solenoid 300) the attractive force ofthe coil I 30 increases but the plunger armature 30f is pulled into thesolenoid 300 with increased strength, moving it at a rapid rate of speedagainst the armature 44 and with a sufiicient momentum to break sucharmature 44 away from the core 30a, especially as the lever armavailable to the plunger armature 30 is greater than the lever armavailable to the core 30a. The ease with which the armature 44 may bebroken away from thecore 30a is aided by the use of the non-magneticmember 30b interposed between the core 30a and the armature 44.

Assuming the flame I 0a of the lamp to be burning under normalconditions and the atmosphere within the region of the flame to benormal, in which circumstance the thermostat element I8 is in its closedposition and the thermostat element I1 is in its open position, and theflame-snuffer element I2 to be in its retracted position, the path ofthe circuit embodying the above-named parts is as follows:

Current source I9, conductor 23, conductor 24, closed terminals ofthermostat element I 6, conductor 25, winding I5, conductor 26,conductor 21, coil I30 and solenoid 30c, conductor 32 to current sourceI9. The winding I5, being thus energized, retains the snuifer element I2in its non-operative position. Also, under such circuit conditions, thesolenoid 300 is energized to hold the armature 44 in its attractedposition, whereby the semaphore 33 is in its elevated, i. e.non-indieating position and the aural and visual alarms 3| and 32respectively are non-operated.

Assuming, now, the presence of an explosive gas within the region of thelamp flame I0a, or the presence of any gas tending to increase thetemperature of the flame, such increase of flame temperature effects theclosure of the terminals of the thermostat element I1, under whichconditions, the circuit is:

Current source I9, conductor 23, conductor 24, terminals of thermostatelement I8, conductor 25, winding I5, conductor 21, solenoid 30 andsolenoid 30c, in parallel, conductor 32 to current source I9, underwhich circuit conditions, the

winding I5 is sufliciently deenergized because of the short circuitbetween conductors 25 and 21 through thermostat elem nt I 1, thusreleasing the snufl'er element I2, w ereby the flame I0a isextinguished.

Upon the extinguishing of the flame I0a as above described, thetemperature within the device will bec ome rapidly lowered resulting inthe ultimate opening of the engagement between the elements of thethermostat I1 and also the opening of the engagement between theelements of the thermostat I8. Immediately the thermostat I8 is openedthe resistance 43 is placed in energizing circuit above described. Undersuch conditions the amount of current delivered to the windings 30 and3004s lowered sufliciently to perthe armature 44 moves the semaphore 33into 'opened and remaining open) the position to be observed. Theengagement of the contact plate 63 .with the contacts 36 completes 'twocircuits one of which extends from a source of current I3, conductor 23,contact plate 63, contact 36, conductor 31, lamp'32, conductor 33,conductor 32 back to source of current N. The lamp 3221s lighted. Also acircuit is closed from source of current 19, conductor 23, bridgingcontact 63, contact 36, conductors 39 and 40, audible signal 3!,conductors 4i and 32 back to source of current l3.

To start the device in operation again, the operator will start the.flame Ia and will manually move the armature l3 into engagement withthe core surrounded by the winding ii. The thermostat I8 ismadesensitive enough so that the terminals thereof will" close immediatelyafter-the flame Illa is started in operation, and therefore the originalenergizing circuit above traced will be completed and the armature l3held in position to hold the snufling device il in the position shown inFig. 1.

Assuming the presence of a gas within the region of the gas fla e Wu,tending to decrease the temperature ofsthe flame, the reduction of flametemperature eflects the openi g of the terminals of the thermostatelement I 3 (the terminals of the thermostat element it having beencircuit under such conditions, ,is:

Current source it, conductor 23, resistance 43, winding l5, conductor26, conductor 21, solenoid 3t and solenoid c in parallel, conductor 3 iconductor 32, to current source it Under suchclrcuit conditions, thereduction in current potential across the winding 63 and the solenoid360 as in the above assumed circumstance, permits the withdrawal of therelay ture at, accom by the actuation of the alarm or alarms, eithermechanically and/or electrically, similarly as above set forth.

Under the circumstance of presence of a noncombustion supporting gaswithin the region of the lamp flame ltd, the winding se or the snuflerelement l2, may be. arranged either to efl'ect the releaseof the smifierelement 62 to extinguish the flame 03a, or to retain the snufler element92 in its non-operative position, as may be desired.

ergization of coil i313 to actuate the 'aural and/or visible alarms,accompanied by extin the lamp flame.

A system for detecting and alarm eflecting for a plurality of detectionlocationsmay comprise individual circuit ts in duplicate of the abovedescribed circuit parts, including individual visual and/or aural alarmsselectively for such respective circuits.

Desirably, detection'and alarms efl'ecting for a plurality of detectionlocations, maybe had by circuit arrangement embodying common wiring. Forexample, in the embodiment illustratedin Fig. 1, in addition to theabove described detection location oi the lamp It, a lamp If may bepositioned at a location other than that of the lamp ll. The partsassociated with the lamp ID 'are designated by like reference characterswith a prime suflix. In addition to such like parts, there is theconductor 46 interconnecting the juncture 34' with the conductor 23.

For selective operation or the semaphore 33', lamp 32', or other visibleindicator, like circuit and associated parts are employed, correspondingto the above circuit and associated parts, designated by like referencecharacters with a prime suflix. Inaddition to these parts the 'conductor41 connects the terminal of the solenoid 33c with the conductor 32. Bysuch arrangement, the

semaphores 33 and 33' are selectively operated respectively upondetection at the locations l3, l0, and likewise the lamps or visiblealarms 32 and 32'.

Also, as is illustrated in Fig. 1, the bell or other aural alarm 32 isactuated in common under the condition of detection or presence of anexplosive or other flame temperature increasing gas or ofa flametemperature decreasing gas at the stated locations i6 and I0, andsimilarly for any additional locations as may be desired.

It is understood that the bridging contact 63 and the associatedcontacts 35, 36, may be in the form of a so-called mercury switch,usually of pivotal type, the (mercury functioning as the jointurecontacting material. In such mercury type switch (not shown) the hollowbody, usually of glass, is rocked to and fro by direct or indirectconnection with the relay armature M, suitable linkage or otheroperating connections being provided for the mechanical actuation of.the semaphore 33.

I In the use of a common alarm or other indicator, such as the bell M orother aural device, say for a two lamp system, and assuming thatdetection of the presence of a flame temperature increasing or flametemperature decreasing gas to be indicated, accompanied by theextinction of tiomal conductor M with the lead 38a for connection withthe. conductor 40. An additional contact is provided at the terminus ofthe conductor 3t,'nainely the contact 52, positioned to be engaged bythe bridging contact 63 when the relay armature 33 is in its attractedposition. Fig. Zillustrates the setting of the movable contact am 6311.of the three-way switch 66 for interconnecting the contact 33, throughconductor 3i,- lead 33a, with the conductor 46.

afiting gas at the location of the lamp I6, giving rise to theretraction of the relay armature 44 by its spring 45, to thealarm-indicating position,

1..., g the detection of a flame temperatureas is illustrated in Fig. 3,the attendant upon observing such situation throws the movable contactarm 50a. of the three-way switch from the indicated full line positionto its indicated dot and dash line position 501), thus interrupting thecircuit through the common alarm 3| with respect to the contact 35. Whenthe trouble on this particular detecting circuit is cleared, armature isattracted by its relay 30, which again causes the signal 3| to sound,apprising the attendant of the changed condition. The attendanttherefore operates the three-way switch 50 to. bring the arm 50a thereofinto engagement with the conductor 31, as indicated in Fig. 2.

The physical apparatus to be located at the various stations designed tobe protected by our improved invention may take any form desired. InFigs. 4 and 5 there is shown one form of preferred apparatus, such formbeing adapted for either stationary or portable use. Referring to suchfigures, 64 designates a tank or fuel font containing the liquid fuel65. Through the upper end plate 6 6 of the font 64 extends the tubularmember In through which passes the wick 68, such wick extending into thebody of the fuel 65. The wick 68 extends upwardly slightly beyondtheupper end of the tubular member ID, and in a position to be engaged bythe sparks generated by a mechanical lighting device 69 secured to the30 upper face of the font end plate 66.

Secured to the upper face of the plate 66, by screw 10, is a bracket H,in which may be adjustably secured the thermostats I1 and I8, theposition of such thermostats l1 and I8 being such that they are acted.upon by the flame Ilia, as above described with respect -to Fig. 1.Leading from the thermostat I1 is a cable 12 containing the conductors24 and 25, and leading from the thermostat I8 is the cable 13 containingthe conductors 21 and 28.

Adjacent to the candle I and the bracket ll, and-secured to the plate66, is the electromagnet l5, having associated therewith the snufler l2and armature I6. Also on the plate 66 is secured the resistance 43. Onthe plate 66 and surrounding the assembly of elements Just described, isa spider frame of metal including a lower ring plate 14 and an upperring plate 15, in which frame is a cylindrical glass tube It. Secured tothe spider frame and thus to the font 64, is an upper frame 11, intowhich the thermo-- stats I! and I8 may extend. Within the upper frame 11and forming a cover is a wire mesh screen 18. I

The entire assembly thus conforms to a regulation miners lamp. Thevarious parts are readily disassembled to allow access to the deviceswithin the glass tube 16, and to permit the operator to fill the font 64and operate the mechanical lighting device 69.

Also mounted'on the plate- 66 is the coil or resistance 43.

The apparatus is adapted to rest on a support,

or to be hung on a hook by means of the eye 19 secured to the top of theframe I1.

Our system may also be arranged to respond to the condition ofshort-circuit of the line, in which circumstance the current through therelay winding is increased. To meet such condition the relay winding iscoordinated to provide for the release of the armature, and thus effectclosure'of the alarm circuit or circuits.

Whereas we have described our invention by reference to specific formsthereof it will be understood that many changes and modifications may bemade without departing from the spirit of the invention.

We claim:

1. The combination of an open flame exposed to an atmosphere which wouldaffect the combustibility of the flame to thereby vary the temperatureof the fiame,.means for directly engaging with and extinguishing theflame, a circuit,

means in said circuit controlling the flame extinguishing means, and athermostat controlling a break point in said circuit, said thermostatbeing exposed directly to the heat from the flame and operable upon alowering of the temperature of the flame to control the circuit foroperating the flame extinguishing means, whereby said flameextinguishing means engages with and extinguishes the flame.

2. The combination of a circuit, temperature responsive circuit closingdevices in said circuit directly responsive to flame temperature, one ofsaid circuit closing devices being normally open and the other of saidcircuit closing devices being normally closed, a flame extinguishingmeans for extinguishing a flame by direct engagement therewith, andmeans in said circuit responsive to the operation of either of thecircuit closing devices for operating the flame extinguishing means.

3. The combination of an operating circuit, a flame snufllng device,means in said circuit for controlling the operation of the flamesnufllng device, a thermostat in said circuit exposed to the heat of aflame which is responsive to a lowering of the temperature of the flamefor operating said last named means to thereby 'extinguish the flame.

4. The combination of a signal, a flame snufflng device, an electriccircuit for controlling the signal, means in said electric circuit forcontrolling the operationof the flame snufling device, and thermostatmeans exposed to the direct action of the heat emanating from said flameand controlling said last named means for operating the signal andoperating the flame snufling device to extinguish the flame upon avariation in the temperature of the flame.

HARRY A. DODGE. CHARLES J. DIETRICH.

